Magnetic valve with lost motion connection



Sept 15, 19 R. D. GRAYSON 3,528,639

MAGNETIC VALVE WITH LOST MOTION CONNECTION Filed Jan. 2. 1968 FIG 2',

A TTOZA/(EV United States Patent 3,528,639 MAGNETIC VALVE WITH LOST MOTION CONNECTION Richard D. Grayson, Arcadia, Calif., assignor to International Telephone and Telegraph Corporation, a corporation of Delaware Continuation-impart of application Ser. No. 617,786, Feb. 20, 1967. This application Jan. 2, 1968, Ser. No. 694,902

Int. Cl. F16k 31/06 US. Cl. 251-75 Claims ABSTRACT OF THE DISCLOSURE A magnetic valve in which a valve member is connected through a lost motion connection to an armature which is controlled by magnetic actuating means. Means is provided for recapturing lost motion between the armature and valve member after the latter is unseated from its valve seat so that total armature movement is utilized to produce an equal valve movement. An improved electromagnetic actuating assembly is disclosed which is operable by very low electric signals, such as from a thermocouple type pilot generator.

This application is a continuation-in-part of my copending appli ation Ser. No. 617,786, filed Feb. 20, 1967, now Pat. No. 3,387,537 assigned to the assignee of the present application. The benefit of the filing date of said co-pending application is therefore hereby claimed for this application.

BACKGROUND OF THE INVENTION The present invention relates generally to a magnetic valve and, more particularly, to a magnetic valve directly actuatable by low level electric signals to control the flow of a low pressure fluid.

In the field of heating control and particularly in the control of home heating units, it is desirable that means for controlling the flow of heating fuel to the burner can be actuated rapidly, in a sure and reliable manner, by relatively low-level electric voltage signals. For example. it would be highly beneficial to be able to use the output of a pilot generator, consisting of a series of thermocouples, for directly controlling the fuel valve. More particularly, a satisfactory valve means for this purpose should be capable of operating from a source voltage of 125 millivolts approximate minimum and against a gas back pressure of approximately /2 p.s.i.

It is, therefore, a primary object of the invention to provide a magnetic valve actuatable by low level electric signals in a sure and reliable manner.

A further object of the invention is the provision of a magnetic valve actuatable by electric signals of as low as 125 millivolts.

Another object is the provision of an improved magnetic valve of the described character that is straight forward in design and inexpensive to manufacture.

SUMMARY OF THE INVENTION According to the principal aspect of the present invention, there is provided an electromagnetically operated fluid control valve in Which the armature that carries a valve closure member is disposed within the range of magnetic influence of a magnetic actuating device. The valve closure member is connected through lost motion connecting means to the armature so that upon initial movement of the armature towards the magnetic actuating means, when the latter is energized, armature movement is relatively unrestrained. As the armature approaches the magnetic actuating device, its pulling strength is substan- "ice tially increased. At this time, the armature engages a limitstop on the valve closure member to withdraw the latter from the valve seat. Spring means is provided for recapturing the lost motion, which results from the initial movement of the armature with respect to the valve closure member, after the valve is opened so that total armature movement is utilized to produce an equal valve movement. As a consequence, only a relatively low-level electric signal is required in the present invention to produce substantial valve movement.

According to another aspect of the invention, there is provided an improved electromagnetic actuating structure which includes an elongated helical coil assembly wound about a core. Core extensions providing relatively flat surface areas connect the core ends and are disposed along the same long side of the coil. A commensurate long armature is disposed slightly spaced from the core ex: tensions and carries a valve closure member for sealing engaging a valve seat and closing the same when the coil is de-energized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational sectional view of the magnetic valve of the invention.

FIG. 2 is a sectional view taken along the line 22 of FIG. 1.

FIGS. 3 and 4 are greatly enlarged views of the special valving member of the invention shown in the closed and open positions, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now particularly to FIG. 1, the magnetic valve 10 of the invention is seen to include in its major elements an enclosure 11 with an inlet 12 and an outlet 13, valve controlling means 14, and closure member '15. In general operation, the valve controlling means 14 is selectively actuatable to relate the closure means 15 to the outlet 13 in such manner as to permit a fluid, fuel gas for example, provided at the inlet 12 to pass therethrough to burner apparatus (not shown) located downstream. Upon deenergization of the means 14, the closure means is returned to the closed position shown in FIGS. 1 and 3, stopping fluid flow.

The enclosure 11 is fundamentally an elongated threesided, rectangular body member 16 having its open side closed by a cover 17. Preferably it is of cast construction of a nonmagnetic material and sufficiently rugged to withstand the shocks and vibrations associated with its normal use. The fluid inlet 12 is made at a threaded opening 18 in one end of the body member 16. The outlet 13 is provided at a similarly threaded opening 19 formed in the side wall of the enclosure 11 opposite the open side and at a point located displaced slightly from the midpoint in a direction toward the inlet. A fitting 20' received within the outlet opening 19 has a continuous, raised circular portion 21 that serves as a valve seat and onto which the closure member 15 bears to close ofl fluid flow. The cover is secured over the open side of the enclosure by any suitable means such as screw members 22.

Valve controlling means 14 includes a cylindrical magnetic core 23 provided with a helically wound coil 24. The ends of the core extend slightly without the coil and are turned down to a smaller diameter. Each end of the core extension plate, 25 at the left and 26 at the right, received thereon through a suitable opening formed in the plate. These extension plates have a generally J-shape in the cross-section shown in FIG. 1, with the leg of the J being directed away from the coil and disposed inwardly away from the open side of the enclosure. A good low magnetic reluctance connection is provided between the extension 3 plates and respective ends of the core 23 by arc welding, for example.

A first pole 27 of generally rectangular platelike construction has its long side portions received within slots 28 and 29, respectively, formed on the inner surfaces of the side walls of the enclosure 11. A second pole 30, identically constructed to pole 27 except longer as seen in FIG. 1, is also mounted in slots (not shown) on the inner wall surfaces of the enclosure so as to be coplanar with the first pole, but spaced laterally as at 31.

For a purpose that will be made clear later, the upper surface of the first pole 27 includes a relatively thin nonmagnetic spacer 32. It may be made of any of a number of different plastics or nonferrous metals. Excellent results have been obtained with such a spacer made of stainless steel, which not only is nonmagnetic but also wears exceptionally well.

Referring now to both FIGS. 1 and 2, a support plate 33 is secured to the lower portions of the enclosure side walls and has inwardly directed extensions 34 and 50 for engaging the respective legs of core extension plates and 26. When fully assembled the support plate serves to hold the extension plates in good surface contacting relation to the lower surface of the poles 27 and 30, as well as secure against sideward movement as shown in FIG. 2. Additionally, the support plate, includes an opening 51 adjacent the end supporting core extension plate 26 for securing one end of a coil spring as will be discussed later.

A magnetically attractable armature 35 is disposed between the poles and the inner wall surface of the enclosure 11. The armature is of substantially the same thickness as the poles, but less wide and shorter in length. Cantilever mounting of the armature to the second pole is made via a mounting plate 36 welded to the armature and a U-shaped spring clip 37 suitably secured to both the plate 36 and pole 30. A coil spring 38 is secured at the opening 51 in the support plate 33 and a similar opening in the plate 36 thereby resiliently urging the free end of the armature toward the outlet 13.

Considering FIGS. 1, 3 and 4 simultaneously and the detailed structure of the closure member 15, it is seen that this member includes a rivetlike pin 39 freely received within an opening 39a in the armature that is substantially centrally located over the space 31 and aligned within the axis of the outlet. The pin includes a first shoulder 40 of diameter larger than that of the pin. The shoulder 40 provides a limit stop engageably by the walls of the armature adjacent the opening therein when the armature moves downwardly with respect to the pin. A second shoulder 41 immediately adjacent the first shoulder, and I serving as one terminus of the pin, has a diameter larger than that of the first shoulder. A conical compression spring 42 is mounted on the pin 39 with one end bearing against the second shoulder 41 and the other end bearing against the lower surface of the armature 35.

The other end of the pin is received on the opposite side of the armature through an axially located opening in a somewhat bell-shaped plate 43, and secured thereto by peening, for example. The plate 43 includes a downwardly extending boss 43a which is normally engaged by the upper surface of armature due to the force of spring 42 against the lower surface of the armature. A cap 44 of a flexible resilient material, such as silicone rubber for example, is received over the bell-shaped plate 43, with the margins thereof folded over and under those of the plate in generous overlapping relationship. It is the outer major surface of this cap that is brought into contact with the raised portion 21 to effect valve closure.

Electrical connector for the coil 24 is made to external energizing circuits by coil lead wires 45, and pin connectors 46 of a conventional female plug 47.

When the magnetic valve described herein is disposed in the valve-closed condition as shown in full lines in FIG. 3 (no energizing voltage on the coil 24), the restoring force in the coil spring 38 urges the free end of the armature upwardly, thereby urging the closure member 15 into sealing relationship with the valve seat 21. In this position of the armature and closure member, when the coil 24 is energized, the power of the armature to unseat the valve element 15 is relatively weak, due to the substantial distance between the armature and the poles 27 and 30. As a consequence, if the closure member 15 were fixedly mounted to the armature, the valve could not be opened against high gas pressure in the enclosure 11 since the affect of the pressure on the closure member Would prevent movement of the armature toward the magnetic poles.

However, due to the lost motion connection between the valve closure 15 and armature 35, movement of the armature toward the poles 27 and 30, upon energization of the coil 24, is generally unrestrained except for the relatively weak spring 42. Thus, the armature moves through a limited travel independent of closure member 15 until it engages the shoulder 40 on the pin 39, as shown in phantom lines in FIG. 3. After the armature has moved this distance, it is capable of exerting a much stronger pull because of the reduced space between the armature and the poles 27 and 30 of the magnet. The additional pulling force on the armature makes it possible to lift the valve closure member 15 off the seat 21 by exerting force directly against the shoulder 40 on pin 39. After the valve member 15 lifts off the seat, the excessive gas pressure which had held the valve closed is relieved. As a consequence, the relief in pressure permits the spring 42 to return the valve member 15 to its normal position relative to the armature 35, as seen in FIG. 4, thereby recapturing the lost motion which occurred during the initial movement of the armature with respect to the valve element. This spring 42 thereby permits full advantage to be taken of the total armature movement to produce an equal valve movement. Without the spring 42, it would be possible for the gas pressure within the envelope 11 to seat the valve member against the valve seat 21 even after the armature has been moved toward the magnetic pole 27 and 30, particularly if the entire valve structure 10 were mounted on its end, which is its normal position in practice, or if it were in an inverted position. Since the spring 42 permits full advantage to be taken of the total armature movement, it is seen that relatively short armature movement is required to actuate the valve and, hence, only lowlevel electrical signals are required for actuating the armature.

When full attracted, the armature is held very slightly spaced from the opposed pole faces by spacer 32. This spacer prevents sticking or continued adherence of the armature and poles that could otherwise result on deenergization due to remanence in the poles.

It is seen, therefore, that in the practice of the present invention, a magnetic valve is provided which can operate directly from a pilot generator furnishing voltage signals as low as millivolts and against a fluid pressure of at least 0.5 p.s.i. The improved performance is achieved in part through use of an elongate large-area armature magnetically coupled to a magnetic core by extensions and poles of correspondingly large area, and with a closure member resiliently carried by the armature through a lostmotion connection. A valve of the character described has exceptionally long life, is fast acting, and highly reliable with the valve closure member being able to compensate for wearing as well as a certain degree of variation in parts encountered during normal manufacturing.

While the invention has been described in connection with a specific form, it is to be understood that numerous other embodiments could be made without departing from the spirit of the invention.

What is claimed is:

1. In an electromagnetically operated fluid control valve having magnetic actuating means, a magnetically attractable armature disposed within range of magnetic influence of said actuating means, and a closure member carried by the armature for selectively closing the outlet of an enclosure provided with pressurized fluid when the actuating means is de-energized and opening the same upon energization of the actuating means, the improvement comprising: lost motion connecting means between said closure member and said armature, said connecting means allowing initial, relatively unrestrained movement of said armature toward said actuating means and relative to said closure member until said armature is closely adjacent to said actuating means, and causing withdrawal of said closure member from said outlet upon further movement of said armature toward said actuating means, thereby opening the same, and said connecting means including means for recapturing, during said further movement of said armature, the lost motion between said closure member and said armature which results from the relative movement of said armature with respect to said closure member during said initial movement of said armature, said magnetic actuating means including a magnetic core, a winding inductively related to the core, first and second pole extension means arranged in separate, low magnetic reluctance relation to the respective opposite ends of the core, the extension means each having an end portion angularly formed toward the other forming a single pole plane with the ends of the end portions spaced from one another whereby when an energizing signal is supplied to the winding, the armature is attracted toward the pole plane, and said lost motion connecting means including pin means on said closure member passing through an opening in said armature, which opening registers with the space between said end portions.

2. A fluid control valve as in claim 1, in which a relatively thin nonmagnetic spacer is secured onto one of the extension means end portions to lie substantially in the pole plane whereby the armature can be attracted closely to the pole plane and yet remain sufficiently spaced therefrom as not to be held by remanence when the winding is deenergized.

3. A fluid control valve as in claim 1, in which the end portions are separate from the remainder of the extension means, and support means to hold the remainder of the extension means in good bearing contact with the end portions.

4. A fluid control valve as in claim 3, in which the remainder of the extension means include a pair of platelike means of substantially J-shape cross-section, each platelike means having an opening for receiving the respective core end therein, the core ends and walls defining the openings in the platelike means being welded to form a low magnetic reluctance junction.

5. A fluid control valve as in claim 4, in which the support means engages the J cross-leg of the platelike means and forces it into contact with the respective end portions of the extension means.

References Cited UNITED STATES PATENTS 1,282,275 10/1918 Morris 251-129 2,414,236 1/ 1947 McCarty 25l-l38 X 2,596,409 5/1952 Johnson et al. 25l-129 X 2,827,923 3/1958 Sadler 25l129 X 2,922,614 1/1960 Nickells 251l X 2,947,510 8/1960 Ray 251138 X ARNOLD ROSENTHAL, Primary Examiner US. Cl. X.R. 

